Prescription opioid use disorders (OUDs) are the fastest growing form of drug abuse and prescription opioids are now the most common cause of accidental drug overdose in the U.S. As more than half of Operation Enduring Freedom/Operation Iraqi Freedom (OEF/OIF) veterans have been diagnosed with a painful condition they are potential candidates for opioid therapy and are at risk for these OUDs. An October 28, 2009 Veterans Health Administration (VHA) pain management directive stressed the risks associated with opioid use, including OUDs, and mandated certain clinical changes. New VHA opioid prescribing guidelines will be released in late 2009 or early 2010. To provide safe, high-quality care for CNCP among veterans, particularly OEF/OIF veterans, we need to understand whether and how veteran-specific issues and system and provider factors affect likelihood of developing OUDs, and rigorously evaluate trends in chronic opioid use, misuse, and OUDs. Aim 1. Use univariate statistics to characterize clinical and demographic characteristics of four groups of veterans in VA care: 1) opioid users, 2) chronic users, 3) chronic opioid users with pharmacy profiles suggestive of opioid misuse, which we term possible opioid misuse, and 4) individuals with diagnosed substance abuse/dependence. Aim 2. Use event history analysis and multi-level models to assess geographic variation and identify patient (sociodemographic and clinical) and treatment (clinical settings) factors associated with a. Chronic opioid use among veterans with any opioid use b. Possible opioid misuse among veterans with chronic opioid use c. Discontinuation of chronic opioid use, among veterans with chronic opioid use d. OUD diagnosis in veterans with possible opioid misuse, and in veterans with chronic opioid use. Aim 3. Use trend analyses to investigate rates of chronic opioid use, possible misuse, discontinuation of chronic opioid use, and diagnosed OUDs in the three years prior to the release of the pain directive and guidelines (FY08-FY10) with rates in the first full three years after the release of the directive and guidelines (FY11-13). Methods: We will utilize secondary data analysis of six years of VA administrative data (FY08-FY13), with separate analyses for OEF/OIF veterans and all veterans. PUBLIC HEALTH RELEVANCE: This study will allow us to better establish the extent of use and abuse of prescription opioids among veterans; identify risk factors for prescription opioid use disorders (OUDs); and assess temporal trends. This type of information is essential for clinicians, as they seek to minimize OUDs in their patients with pain.